trans-Neptunian object

American  

[trans-nep-too-nee-uhn ob-jikt, -jekt, -tyoo-, tranz] / ˈtræns nɛpˈtu ni ən ˈɒb dʒɪkt, -dʒɛkt, -ˈtju-, ˈtrænz /

Or transneptunian object

noun

Astronomy.

1. any celestial object in our solar system whose orbit lies beyond Neptune, including Pluto: there may be some 70,000 trans-Neptunian objects orbiting 30–50 astronomical units from the sun, with diameters of at least 62 miles (100 km). TNO

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trans-Neptunian object Scientific  

/ trăns′nĕp-to̅o̅n′ē-ən /

1. A celestial object that orbits the sun at a greater distance on average than Neptune.

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Etymology

Origin of trans-Neptunian object

First recorded in 1920–25